This directive permits you to control the order in which your jobs will be run by specifying a positive non-zero number. The higher the number, the lower the job priority. Assuming you are not running concurrent jobs, all queued jobs of priority 1 will run before queued jobs of priority 2 and so on, regardless of the original scheduling order.

The priority only affects waiting jobs that are queued to run, not jobs that are already running. If one or more jobs of priority 2 are already running, and a new job is scheduled with priority 1, the currently running priority 2 jobs must complete before the priority 1 job is run, unless Allow Mixed Priority is set.

If you want to run concurrent jobs you should keep these points in mind:

-  See :ref:`ConcurrentJobs` on how to setup concurrent jobs.

-  Susan concurrently runs jobs of only one priority at a time. It will not simultaneously run a priority 1 and a priority 2 job.

-  If Susan is running a priority 2 job and a new priority 1 job is scheduled, it will wait until the running priority 2 job terminates even if the Maximum Concurrent Jobs settings would otherwise allow two jobs to run simultaneously.

-  Suppose that susan is running a priority 2 job and a new priority 1 job is scheduled and queued waiting for the running priority 2 job to terminate. If you then start a second priority 2 job, the waiting priority 1 job will prevent the new priority 2 job from running concurrently with the running priority 2 job. That is: as long as there is a higher priority job waiting to run, no new lower priority jobs will start even if the Maximum Concurrent Jobs settings would normally allow them to
   run. This ensures that higher priority jobs will be run as soon as possible.

If you have several jobs of different priority, it may not best to start them at exactly the same time, because Susan must examine them one at a time. If by Susan starts a lower priority job first, then it will run before your high priority jobs. If you experience this problem, you may avoid it by starting any higher priority jobs a few seconds before lower priority ones. This insures that Susan will examine the jobs in the correct order, and that your priority scheme will be respected.

